Untangling the relationship between gender and chronic pain is no small feat. It is easy enough for the statisticians to tell us that women are at a significantly increased risk for chronic musculoskeletal pain, widespread pain (including fibromyalgia), osteoarthritis, rheumatoid arthritis, headache (including migraine) and temporomandibular joint (TMJ) dysfunction.
But what are the biologic, psychologic and social factors that might explain this pain burden women seem to bear to a much greater degree compared to men?
Experimental pain studies have shown that women display a greater sensitivity to pressure, electrical and thermal stimuli. Positron emission tomography studies have shown that when a stimulus is adjusted to elicit the same pain report in men and women, men show an imaging pattern consistent with sensory process dominance; in contrast, women showed an imaging pattern suggestive of a more emotional integration of the same noxious input.
And what would a discussion of the differences between men and women be without at least a brief mention of hormones?
Girls do experience an increased incidence of migraine and TMJ disorders at puberty. In addition, fluctuating estrogen levels during the menstrual cycle appear to worsen musculoskeletal pain and migraine symptoms. Estrogen may also negatively affect the body’s natural opiate system.
Psychological research has shown that women focus on the more overwhelming and negative emotional components of pain. This, however, does not completely explain the sex differences in diffuse noxious inhibitory controls (DNIC): Men show greater DNIC, which is a descending pathway that modifies sensory pain input to the brain.
Finally, gender roles, or at least the expectations for the role of gender, influence pain perception. The social “norm” for females is characterized by an acceptance of pain as a natural part of life, and the freedom to express their feelings about the pain. Greater femininity generally indicates more intense experimentally induced pain.
Unfortunately, women are not only at risk for more of certain types of pain; they are at greater risk for suboptimal pain treatment. One theory for this might be the relative willingness of women to discuss their pain: When the supposedly more stoic male finally does say something, perhaps he is taken more seriously. Nonetheless, a woman’s psychological symptoms tend to be taken more seriously than the grumblings of the male.
As is so often the case, perceived norms provide the obstacle course in the quest to become normal.